In previous posts, I discussed the SpiderMonkey command line shell js and how to add support to it to enable full access (read, write, create, copy, delete, etc.) to the local filesystem via the File object and the NSPR library. While rumaging around in the source code and documentation for js, I found that js partially supported the EX4 XML extension via a user configurable option. This post looks at what it takes to load an XML document into js from your local filesystem, process it and write out the resulting document to your local filesystem using File objects and